Heat generator and exchanger, and expansion joint therefor



Nqv. 26,- 1963 G. PEOPLES 3,111,939

' HEAT GENERATOR AND EXCHANGER,- AND EXPANSION JOINT THEREFOR Filed June 19, 1961 2 Sheets-Sheei '1 E NTOR.

ATTORNEYS.

Nov. 26, 1963 EO LE 3,111,939

HEAT GENERATOR AND EXCHANGER, AND EXPANSION JOINT THEREFOR Filed June 19, 1961 2 Sheets-Sheet 2 NVENTOR' ATTORNEYS United States Patent 3,111,939 HEAT GENERATDR AND EXCHANGER, AND EXPANSIQN JQII NT THEREFOR Graydon Peoples, Marshalltown, Iowa, assignor to Lennox Industries, Inc., Marshalitown, Iowa, in corporation of Iowa Filed June 19, 1961, Ser. No. 118,073 2 Claims. (Q1. 126-104) This invention relates to a furnace construction for churches, stores, factories and the like, having a heat generator and exchanger, and an expansion joint therefor, the present application being a division of my copending application Serial No. 13,245, filed March 7, 1960.

One object of the invention is to provide a stainless steel heat exchanger of large cylindrical shape which can withstand the most severe temperatures and can be fired at peak efficiency with the furnace mounted in any oriented or installed position, there being no baflles to warp or burn out inside the primary heat exchanger, and an arrangement being provided such that the combustion gases travel the entire length of the primary heat exchanger into a rear breeching and then into the secondary flue passages from which they travel to the front of the furnace and into a flue outlet.

Another object is to provide a novel type of expansion joint between the heat exchanger and the rear breeching that allows the heat exchanger to expand and contract under changing temperature conditions without metal fatigue.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my heat generator and exchanger whereby the objects above contemplated are attained, as hereinafter more fully set forth, pointed out in my appended claims and illustrated in detail on the accompanying drawings, wherein:

FIG. 1 is a perspective view of a furnace construction embodying my invention, parts thereof being broken away to show internal details;

FIG. 2 is an enlarged perspective view of the heat generator and exchanger thereof; and

FIG. 3 is a vertical sectional view on the line 3-3 of FIG. 2 showing an expansion joint at one end of the heat generator and exchanger.

On the accompanying drawings I have used the reference numeral to indicate in general a housing for my furnace construction. An acoustically lined front door 22. is provided at one end thereof spaced inwardly from which there is a double-walled partition 24. The space between the door 22 and the partition 24 constitutes a burner vestibule in which all controls are hidden from sight, thus eliminating accidental bumping thereof and tampering therewith.

inward of the partition 24 I provide a stainless steel tubular primary heat generator and exchanger 26 having a front wall 28 terminating in a burner receiving tube 30. As shown in FIGS. 2 and 3, the rear end of the heat generator and exchanger 26 is provided with an expansion joint comprising a front plate 34 and a rear plate 36 connected by thimbles 38 and ltl to a rear wall 32 of the heat exchanger and a rear flue box 42 respectively. The peripheries of the plates 34 and 36 are riveted or otherwise suitably secured together and the plates are spaced as illustrated in FIG. 3 so that the spacing between them may decrease as the heat exchanger expands and increase as it contracts, thus producing a breathing action without straining the metal and thereby eliminating metal fatigue. This is a desirable feature under changing temperature conditions as it eliminates undesirable fracturing of joints or metal walis of the heat generator and exchanger and associated parts.

The rear flue box 42 has a plurality of lines 44- communicating therewith and extending forwardly to communicate in turn with a front flue box 4s. Each flue 44 has a corrugated baflie 45 therein and the fines constitute a secondary heat exchanger. The partition 24 constitutes a front wall for the flue box 4-6 and has a suitable opening therein through which the products of combustion from the primary exchanger 26 and the flues 44 flow into a blower housing 5%). To hold heat losses in the housing 29 to a minimum, a corrugated metal radiation shield 11% (see F165. 1 and 3) is provided, separated from the rear wall of the housing 26 by an air space 1tl2.

The blower housing 59 is a combination induced draft and combustion air blower housing and has a rear wall 52 and a front wall 54. The rear wall 52 is positioned against the partition 24.

A partition 58 divides the housing 5% into an induced draft blower section receiving the products of combustion and containing an induced draft blower wheel 69, and a combustion air blower section containing a combustion air blower wheel 62. The induced draft blower section has a discharge opening 64 communicating with a flue outlet section 66 of the housing 5% The flue section 66 has a top flue opening with which a flue extension 74 is associated. The blower wheel 69 directs the products of combustion into the flue outlet section 66.

The combustion air blower wheel 62 receives air from the burner vestibule through an opening 86 in the front wall 5- 3 of the housing 5%, and discharges it into the lower part of tne housing to enter a draft tube 114 of the burner unit.

Both blower wheels 6i? and 62 are mounted on the same blower shaft 9% supported by a bearing assembly 92 which in turn is supported on the front wall 54 by three supporting brackets 94. The shaft 90 is driven by a V-beit 96 from a motor 9% whereby both blower wheels on and 62 are driven by the same motor. By mounting both blower wheels 61) and 62 on a single shaft and driving them from a single motor, both manufacturing costs and maintenance are reduced to eifect extra economy, and fewer parts are involved to service. This arrangement also contributes to quietness of operation. By having the blower wheels on opposite sides of the partition 58 which is heated by the products of combustion (usually about 600 F.) flowing past it from the discharge opening 64 to the flue outlet section 66, all combustion air is preheated for maximum efiiciency of operation of the burner. The bearing assembly 92 is isolated from the hot blower wheel by the cooler blower wheel as and the partition 58, and since the bearing assembly is located in the inlet opening 86 where room air at about is flowing into the blower wheel 62, the bearing assembly runs relatively cool because of room air being constantly drawn thereover, yet both blowers can be regulated separately to obtain the most efiicient combustion and provides the correct draft for particular installations by providing separate dampers for each.

Both blower wheels are also simultaneously operable during pre-purge and post-purge periods to provide rapid purge of the combustion chamber by blowing room air into its intake end and withdrawing gases from its discharge end. It will be noted that the burner axis and the axes for the blowers and their motor are all parallel to each other so that the entire furnace construction can be installed upright as shown, on its side (horizontal), or

inverted and suspended from the ceiling if desired to suit a variety of different installations and fit various available space shapes.

The furnace housing 28 may be mounted on a blower housing shown generally at 164 having discharge opening 106 for air as indicated by arrows in FIG. 1 to circulate around the primary and secondary heat exchangers 26 and 44. This air then flows into the top of the housing 20 which serves as a plenum chamber for heated air discharge outlets 1G8 provided with adjustable deflector blades 116 so that the heated air is properly directed throughout the area to be heated as desired for comfortable temperatures at working levels. Alternatively, duct distribution systems can be associated with the outlets 1&3.

The blower housing 194 has a pair of blowers 172 mounted therein. The blower wheels 173 of the blowers 1'72 are mounted on a single shaft 175 and driven by a belt 174 from a motor 176. Grills 178 permit entrance of air into the blower housing 1&4 to be forced by the blowers around the heat exchangers 26 and 4-4. and through the plenum chamber thereabove to the discharge outlets 10S.

Describing next the main elements of the burner unit indicated generally as B, the burner receiving tube 39 of the primary heat exchanger 26 surrounds the draft tube 114 and supports a cylinder-shaped refractory 118. A nozzle and igniter assembly is shown comprising a fuel oil atomizing nozzle mounted in a support 126 in the draft tube 114, a fuel oil pipe 130 extending from the support 126 and a pair of high tension insulators 132 supporting spark electrodes 134 for the ignition of oil. A fuel oil pump 160 is provided, driven by a belt 162 from the blower shaft 90 and supplies oil to the pipe 130. It is contemplated that multiple fuel oil nozzles may be used where it is desired to perform staged starting and multiple selection rates.

The burner vestibule may have the various furnace controls such as 164 and 166 mounted therein, as well as a solenoid 158 for damper control. An access and inspection door 168 for the burner is also located therein normally covering an opening 17% in the front wall 54 of the housing 50.

Some changes may be made in the construction and arrangement of the parts of my heat generator and exchanger without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may reasonably be included within their scope.

I claim as my invention:

1. In a furnace construction, a combustion chamber, a burner therefor, said combustion chamber comprising a stainless steel cylindrical primary heat exchanger having a receiving end, and a discharge end opposite said receiving end, said receiving end communicating with and receiving the flame from said burner, said cylindrical heat exchanger being adapted to entirely contain the flame from said burner and having a burner supporting sleeve extending from said receiving end to receive said burner, a flue box receiving the products of combustion from said discharge end of said primary heat exchanger and having an expanded portion greater in width than the diameter of said primary heat exchanger, flues extending from the expanded portion of said flue box toward said receiving end and constituting a secondary heat exchanger through which the gases of combustion by-pass the burner flame, a second flue box adjacent said receiving end with which said flues communicate, an expansion joint connection between said discharge end of said primary heat exchanger and said first flue box which includes a pair of thimbles connected to said combustion chamber and said first flue box respectively and a pair of diaphragmlike elements having their inner edges connected to said thimbles and their outer edges connected together to allow both radial and longitudinal expansion and contraction, a casing around said primary heat exchanger, said expansion joint, said flue boxes and said flues permitting flow of air first around said primary heat exchanger and expansion joint and then around said flues, and a flue outlet receiving the products of combustion from said second flue box.

2. In a furnace construction, a burner, a cylindrical primary heat exchanger communicating with and receiving in one end thereof the flame from said burner and constituting a combustion chamber adapted to entirely contain said flame, a flue box receiving the products of combustion from the other end of said primary heat exchanger and having an expanded portion greater in width than the diameter of the heat exchanger, flues extending from said flue box toward the receiving end of said primary heat exchanger and constituting a secondary heat exchanger, a second flue box adjacent said receiving end with which said flues communicate, an expansion joint between said primary heat exchanger and said first flue box comprising a pair of spaced plates having their edges sealed with respect to each other and having openings at their centers which are spaced inwardly from their peripheral edges, thimble connections between said openings and said primary heat exchanger and said first flue box respectively, said thimble connections being of less diameter than said cylindrical primary heat exchanger to provide a restriction for the products of combustion beyond the flame contained therein, said expansion joint allowing the heat exchanger to expand and contract both longitudinally and in diameter under changing temperature conditions without metal fatigue, and a casing around said primary heat exchanger, said expansion joint, said fiue boxes and said flues permitting flow of air therearound.

References (Iited in the file of this patent UNITED STATES PATENTS 2,172,667 Nelson Sept. 12, 1939 2,622,589 Tuck Dec. 23, 1952 2,822,800 Hines Feb. 11, 1958 2,928,459 Eastman et al Mar. 15, 1960 2,979,050 Costello Apr. 11, 1961 2,984,235 Johnson et a1. May 16, 1961 3,028,854 Reilly Apr. 10, 1962 

1. IN A FURNACE CONSTRUCTION, A COMBUSTION CHAMBER, A BURNER THEREFOR, SAID COMBUSTION CHAMBER COMPRISING A STAINLESS STEEL CYLINDRICAL PRIMARY HEAT EXCHANGER HAVING A RECEIVING END, AND A DISCHARGE END OPPOSITE SAID RECEIVING END, SAID RECEIVING END COMMUNICATING WITH AND RECEIVING THE FLAME FROM SAID BURNER, SAID CYLINDRICAL HEAT EXCHANGER BEING ADAPTED TO ENTIRELY CONTAIN THE FLAME FROM SAID BURNER AND HAVING A BURNER SUPPORTING SLEEVE EXTENDING FROM SAID RECEIVING END TO RECEIVE SAID BURNER, A FLUE BOX RECEIVING THE PRODUCTS OF COMBUSTION FROM SAID DISCHARGE END OF SAID PRIMARY HEAT EXCHANGER AND HAVING AN EXPANDED PORTION GREATER IN WIDTH THAN THE DIAMETER OF SAID PRIMARY HEAT EXCHANGER, FLUES EXTENDING FROM THE EXPANDED PORTION OF SAID FLUE BOX TOWARD SAID RECEIVING END AND CONSTITUTING A SECONDARY HEAT EXCHANGER THROUGH WHICH THE GASES OF COMBUSTION BY-PASS THE BURNER FLAME, A SECOND FLUE BOX ADJACENT SAID RECEIVING END WITH WHICH SAID FLUES COMMUNICATE, AN EXPANSION JOINT CONNECTION BETWEEN SAID DISCHARGE END OF SAID PRIMARY HEAT EXCHANGER AND SAID FIRST FLUE BOX WHICH INCLUDES A PAIR OF THIMBLES CONNECTED TO SAID COMBUSTION CHAMBER AND SAID FIRST FLUE BOX RESPECTIVELY AND A PAIR OF DIAPHRAGMLIKE ELEMENTS HAVING THEIR INNER EDGES CONNECTED TO SAID THIMBLES AND THEIR OUTER EDGES CONNECTED TOGETHER TO ALLOW BOTH RADIAL AND LONGITUDINAL EXPANSION AND CONTRACTION, A CASING AROUND SAID PRIMARY HEAT EXCHANGER, SAID EXPANSION JOINT, SAID FLUE BOSES AND SAID FLUES PERMITTING FLOW OF AIR FIRST AROUND SAID PRIMARY HEAT EXCHANGER AND EXPANSION JOINT AND THEN AROUND SAID FLUES, AND A FLUE OUTLET RECEIVING THE PRODUCTS OF COMBUSTION FROM SAID SECOND FLUE BOX. 